Compatibility Relationships in Flowering Plants: Role of the S-Gene Complex

1968 ◽  
Vol 102 (927) ◽  
pp. 475-489 ◽  
Author(s):  
Kamla K. Pandey
Keyword(s):  
Flowering Plants ◽  
Gene Complex ◽  
S Gene

scholarly journals Florigen governs shoot regeneration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yaarit Kutsher ◽  
Michal Fisler ◽  
Adi Faigenboim ◽  
Moshe Reuveni
Keyword(s):  
Nitric Oxide ◽  
Shoot Regeneration ◽  
Ectopic Expression ◽  
Flowering Plants ◽  
Regeneration Capacity ◽  
No Donor ◽  
Tobacco Leaves ◽  
Age Related ◽  
Delayed Flowering

AbstractIt is widely known that during the reproductive stage (flowering), plants do not root well. Most protocols of shoot regeneration in plants utilize juvenile tissue. Adding these two realities together encouraged us to study the role of florigen in shoot regeneration. Mature tobacco tissue that expresses the endogenous tobacco florigen mRNA regenerates poorly, while juvenile tissue that does not express the florigen regenerates shoots well. Inhibition of Nitric Oxide (NO) synthesis reduced shoot regeneration as well as promoted flowering and increased tobacco florigen level. In contrast, the addition of NO (by way of NO donor) to the tissue increased regeneration, delayed flowering, reduced tobacco florigen mRNA. Ectopic expression of florigen genes in tobacco or tomato decreased regeneration capacity significantly. Overexpression pear PcFT2 gene increased regeneration capacity. During regeneration, florigen mRNA was not changed. We conclude that florigen presence in mature tobacco leaves reduces roots and shoots regeneration and is the possible reason for the age-related decrease in regeneration capacity.

scholarly journals Investigation of the Role of the Spike Protein in Reversing the Virulence of the Highly Virulent Taiwan Porcine Epidemic Diarrhea Virus Pintung 52 Strains and Its Attenuated Counterpart

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 41 ◽  
Author(s):  
Chi-Fei Kao ◽  
Hui-Wen Chang
Keyword(s):  
Mortality Rate ◽  
Porcine Epidemic Diarrhea Virus ◽  
Rational Design ◽  
Economic Losses ◽  
Diarrhea Virus ◽  
Viral Shedding ◽  
S Gene ◽  
Porcine Epidemic Diarrhea ◽  
Highly Virulent

Porcine epidemic diarrhea virus (PEDV) has continuously caused severe economic losses to the global swine industries; however, no successful vaccine against PEDV has been developed. In this study, we generated four autologous recombinant viruses, including the highly virulent iPEDVPT-P5, attenuated iPEDVPT-P96, and two chimeric viruses (iPEDVPT-P5-96S and iPEDVPT-P96-5S) with the reciprocally exchanged spike (S) gene, to study the role of the S gene in PEDV pathogenesis. A deeper understanding of PEDV attenuation will aid in the rational design of a live attenuated vaccine (LAV) using reverse genetics system. Our results showed that replacing the S gene from the highly virulent iPEDVPT-P5 led to complete restoration of virulence of the attenuated iPEDVPT-P96, with nearly identical viral shedding, diarrhea pattern, and mortality rate as the parental iPEDVPT-P5. In contrast, substitution of the S gene with that from the attenuated iPEDVPT-P96 resulted in partial attenuation of iPEDVPT-P5, exhibiting similar viral shedding and diarrhea patterns as the parental iPEDVPT-P96 with slightly severe histological lesions and higher mortality rate. Collectively, our data confirmed that the attenuation of the PEDVPT-P96 virus is primarily attributed to mutations in the S gene. However, mutation in S gene alone could not fully attenuate the virulence of iPEDVPT-P5. Gene (s) other than S gene might also play a role in determining virulence.

Genomic Variations in ORF3a and ORF1ab Genes of SARS-nCoV2 Strain from Southern Pakistan

2020 ◽  
Author(s):  
Rashid Saif ◽  
Aniqa Ejaz ◽  
Tania Mahmood ◽  
Saeeda Zia ◽  
Abdul Rasheed Qureshi
Keyword(s):  
Host Cell ◽  
Viral Entry ◽  
Binding Capacity ◽  
Its Sequence ◽  
Genomic Variations ◽  
S Gene ◽  
Variation Rate ◽  
Codon Change ◽  
Different Strains

Emergence of COVID-19 pandemic has resulted in 8,578,283 total cases and 456,286 deaths worldwide as of June 19, 2020. We previously analysed genomic variants in two Northern Pakistani SARS-nCoV2 strains against USA and Chinese strains as reference, and hypothesized the putative role of observed variants in low severity of COVID-19 in Pakistan. Due to high variation rate in this virus, we further analysed the whole genome of Southern Pakistani SARS-nCoV2 MT500122 strain (Karachi-Pak) vs NC_045512 (Wuhan1-China) and observed 4 variants (3=SNPs,1=del). Three of variants at g.1604 (del ND447N), SNPs at g.1912 (p.=), g.10582 (p.=) and g.26022 (p.=) in ORF1ab and ORF3a genes respectively. ORF1ab encodes 16 non-structural polyproteins (nsps1-16) and plays role in viral replication. The codon change deletion in its sequence (as observed in MT500122) might have caused conformational alterations particularly in nsp2&5 structures which may obstruct its effectiveness. ORF3a is unique to SARS-nCoV2 and located in-between envelope and spike genes, which assist viral entry into the host cell by interacting with S gene. Alteration in its sequence might have hampered the activation of S gene and affect its binding capacity to host cell ACE2 and NRP1 receptors, which may greatly weaken its pathogenicity in its different strains and hence may vary severity of COVID-19. Nevertheless, intensive data and conclusive wet lab experiments are needed for validating this postulated hypothesis. Moreover, these variants have modifier to silent impact on further 9 genes e.g. M, N, S, E, ORFs 6, 7a, 7b, 8 and 10 as well. Advancements in understanding the role of these Pakistani SARS-nCoV2 genomic variations will be helpful in developing indigenous vaccines, diagnostic kits and drug development.

scholarly journals Immune mechanisms in leukemia role of the Ia antigens.

1977 ◽  
Vol 145 (4) ◽  
pp. 1077-1081 ◽  
Author(s):  
O A Lukasewycz ◽  
J A Frelinger
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Tumor Immunity ◽  
Selective Removal ◽  
Gene Complex ◽  
Protective Capacity ◽  
Ia Antigen ◽  
Immune Mechanisms ◽  
Ia Antigens

We have shown that the selective removal of cells possessing Ia determinants coded by the I-A, I-B, and I-J regions of the H-2 gene complex completely abrogates the protective capacity of nylon-wool-purified T lymphocytes against leukemic challenge. This suggests that the Ia antigen bearing T cells play an important role in tumor immunity.

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